The Airbus Beluga (Super Transporter) is a version of the standard Airbus A300 wide-body airliner, modified to carry aircraft parts and over-sized or awkward cargo. It was officially called the Super Transporter at first, but the name Beluga became popular and has now been adopted as official.

It is used to transfer pieces of other airplanes, even whole cabins. It is used to transfer industrial machinery or components of Space stations as well:

The Antonov An-225 is a strategic airlift transport aircraft which was built by Antonov, and is the world's largest powered aircraft. It measures 84 meters in length (11 more than the A380) and his lifting capacity is of 250 tons. Antonov are used for the transport of very heavy loads , as train wagons...

The design, built to transport the Buran orbiter, was an enlargement of the successful An-124 Ruslan. Mriya (Мрія) means "dream" (inspiration) in Ukrainian.

3. Boeing 747 Shuttle Carrier

The Shuttle Carrier Aircraft(SCA) are two extensively modified Boeing 747 jetliners that NASA uses to transport a space shuttle orbiter.

The SCAs are used to ferry space shuttles from landing sites back to the launch complex at the Kennedy Space Center, but on August 12, 1977, the first free flight by the prototype space shuttle orbiter Enterprise was successfully flown at NASA's Dryden Center.

The picture where as you say Mryia can lift the sky crane (which is actually true) in reality shows An-124 "Ruslan". This is pretty obvious as it belongs to "Volga-Dnieper" company - you can read it on the side, while Mriya has always belonged to Antonov Airlines